YEF 2020 ESP8266 Code
Useful links: Aruduino Studio download - https://www.arduino.cc/en/software ESP8266 pin out - https://randomnerdtutorials.com/esp8266-pinout-reference-gpios/ Library for OLED screen - https://github.com/adafruit/Adafruit_SSD1306
Pin out as used for your YEF box: OLED Screen to ESP8266: VCC -> 3V on ESP8266 GND -> G on ESP8266 SCL -> D1 on ESP8266 SDA -> D2 on ESP8266
Buzzer: Positive side (long pin) - D5 on ESP8266 Negative side (short pin) - G on ESP8266
If you are not powering the ESP8266 via a battery, you can power it from the micro usb port.
If you are powering the ESP8266 via a battery, please connect positive side of the battery to "VIN" on the ESP8266 and the negative side of the battery to "G" on the ESP8266.
Remember, google is your friend when it comes to anything IOT :)